

| Subject: | Re: Aaaaargh! Brake failure (long) |
| From: | Max/Joyce Wellhouse |
| Date: | Tue, 18 Apr 2000 15:31:18 -0700 |
Ezra: I thought the advantage of the DOT 5 silicone brake fluid was that it didn't absorb moisture and that's why it's $30 a quart. Of course this stuff is not recommended for the Vanagon so it's a moot point. Dimwitted moose and Flying Squirrel. -----Original Message----- From: Ezra Hall <ehall@TOGETHER.NET> To: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM> Date: Monday, April 17, 2000 2:03 PM Subject: Re: Aaaaargh! Brake failure (long) >Brent, > The brake fade you are experiencing is due to vaporization of brake fluid (more >specifically, whatever is in your brake lines, it may be a combination of brake >fluid and H2O). What kind of fluid did you use? What is its boiling point? You >mentioned the need to pump once to gain a firm pedal, that is a sign of air >in the brake hydraulic system, how did you bleed the brakes? Did you flush the >lines until clear? When towards the end of bleeding, I always open the bleeders >a minimal amount to keep air from being sucked back past the threads of the >bleeder. You can identify the amount of bleeder opening which allows air to >be sucked past the threads by observing the amount of bleeder opening which >causes more bubbles in the bleed stream (due to a venturi type effect). Also >make sure you close the bleeder before positive pressure is lost. > Can you spin the wheels freely or are the calipers binding? Perhaps if air >is in the system, it is staying slightly pressurized after letting off the brake >pedal causing brake system heating during normal driving. Did you adjust the >rear shoes properly so as not to bind? When driving long mountain passes, I >always use the engine to brake as much as possible (difficult on our Auto Westy, >but still possible). > You can help minimize reduction in braking due to gassing at the pad/rotor >interface by slotting your brake pads. Do this by using two hack saw blades >in parallel to score a groove (approx 1/4" deep) in the center of each pad parallel >with a radia drawn from the center of the rotor (short direction of the pad). >This slot will help gasses escape the pad/rotor interface. > Use a high quality brake fluid. Castrol GT LMA is ok, if you are still experiencing >problems you could move to a higher temp fluid, but make sure you flush it more >often as higher temp/performance brake fluids also absorb moisture at a faster >rate. >Good Luck, be safe! >Ezra >'88 Westy, 94K >'86 944, 260K
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